A number of investigations have been performed over the past few years on high energy density electric cells using positive electrodes that contain insertion compounds in which the negative active material is inserted during charging. The said negative active material is constituted by an alkali metal, in particular lithium. Such electric cells are described in particular in French Pat. No. 77 04 518 published under the No. 2 381 395.
Further, bismuth oxide Bi.sub.2 O.sub.3 has also been recommended for use as a positive active material, as described in "Journal of the Electrochemical Society 1978, vol. 125 No. 1 p. 14" as has the use of compounds such as Pb.sub.2 Bi.sub.2 O.sub.5 and PbBi.sub.2 O.sub.4 as published in "The proceedings of the 11th International Power Sources Symposium No. 7, Brighton 1978", at page 623, published by Academic Press.
However, such compounds which allow high energy density to be obtained are not suitable for producing rechargeable, or secondary electric cells.
Preferred embodiments of the present invention remedy such drawbacks and produce a high energy density electric cell which is capable of undergoing a large number of charge/discharge cycles. Further, such an electric cell is not very expensive to produce.